Drying apparatus



Sept. 22, 1936. A. w. FERRE DRYING APPARATUS 2 Sheets-Sheet l Filed March 23,v 1955 2 Sheets-Sheet 2 QN Nm m W. D m

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Sept. 22, 1936. A. w. FERRE A DRYING APPAlmUs` Filed March 23, 1955 Patented Sept. 22, 1936 UNITED STATES PATENT OFFICE DRYING APBARATUS f Albert W. Ferre, Wellesley, Mass., assigner to B. F. Sturtevant Company, Boston, Mass.

Application Maren 23, 1935,V serial No. 12,609

7 claims.' (Cim-46) l This invention relates to drying systems and relates more particularly to the drying of lumber and the like, in what are known as drying kilns.

`In kilns for the drying of lumber in the form 5 of boards or planks, it is customary to so stack the boards in the upper portion of a kiln, that interstices between the` boards are formed and through which, heated air is blown under forced draft to dry outboth sides ofthe lumber.

l0 In such kilns, it has been customary to produce the forced draft of air by means of a plurality of spaced fans in a chamber below the lumber drying chamber and to heat the air with steam pipes extending longitudinally of the kiln Vin l5 channels between the fan chamber and the drying chamber.

It has been appreciated that the heated air as it passes through the stacked lumber, loses through its absorption of lmoisture and loss of g@ heat its eiectiveness to a considerable degree, with the result that those portions ofthe lumber rst contacted with the drying air, are beneted more than the :following portions in the path of the :airI now, lso ,it has been customary to provide 25 reversible fans for causing the drying air streamV to enter nrst one side ofthe stack to be dried,

and then aiter :a period of time, the opposite side.

' Accordingto a :feature of vthisinvention, an

extended .surface unit heater is associated with .310 each of the spaoedffans a drying rkiln, :a humidiiier, extended surface heater and Yaxfan being provided as afunihthe air :being properly heated and humidied at aplurality oi points adjacent the fans which produce the air movement.

. According'to another Afeature of the invention,

air reversing dampers :are provided between pairs 'of 15ans to :cause zthe heated air to flow towards one side, tor theother side as desired, of the kiln.v

- Anfobjeet of the invention is to provide an eili- :eient for the; drying of lumber and the like. 'Anotherebiect of the invention is to provide in a drying kiln, a plurality of small compact fan and heater units in spacedrelationship for -pro- `ducing the' necessary movement of heated air.

.45 Another `oln'ect .of the'inyention is to `provide fin a dr-yingwkiln, .a plurality fof small. compact llimits in spaced relationship, each unit comprising an extended surface heater; aihumidi-er and afan.

5p Another object of the invention is to reverse .the air .flow of constantly 4,onerat-ing grans in a drying kiln, hy means `of dampers, 'so vas to cause the lair Ato flow toward one 'side or the other side of the fkilnx as desired. n Y

ne Other lobiectsxof'the invention will be apparent Vto pass as will now be described.- i

from the following description takengtogether with the drawings. The invention will now be described with reference to the drawings `of which:

`Fig. 1 is an end view, partially in section, Aof a n drying kiln according to this invention. l

2 is an end View in` section of the kiln of Fig. 1. Fig, 3 is a plan view inv-section of the kiln of Figs.V 1 and 2, and i Fig. 4 is a sectional view along the lines 4-4 of Fig. 3. l

With reference to Figs. l and 2, thelumber to be dried, is stackedy in the drying chamber 5 upon-the member .6 which in turn is mounted upon-the wheels 'I which restV upon thetrack rails 8. ,'Ifhe successive layers o-f lumber 9 are spaced apart to form a plurality ofA horizontal channels Ill through which the drying airis made Outside air enters the duct 9c through the g openings I 0a and II and passes A-into the drying chamber 5 past the-counterweighted damper I2, at the upper portion of the` drying chamber, and past the `counterweighted damper I3 into the fan @5 chamber I4. Mounted Withinthe fan chamber I4 are the plurality .ofspaced fan, heat exchange and humidi-fying units, which as will be described in detail later, heat theair by passing recirculated air from the drying chamber 5 and out- ,so side,v make-up axir which' enters ,through the dampers -I2 and I3, through the air treating .devices, and then force the` heated air upwardly through Vthe grille I5, where it then passes here izontally through the plurality ofV channels Ill between the successive layersof lumber, the `air moving Aas indicated by the arrows of Figs. 1 land 3 to pass from the fan chamber III, under the pressure of thefans 11:11 along `one side of .the stacked lumber, vthen through the channels I0, 4,0 between the successive layers of lumber, and `be- .ing drawn as recirculated air downwardly-along the opposite side of the stacked lumber, into Vthe .suction side ,of` the fans. 1

The Idempers @I6 and l-l are :counterweighted dempers, .similar to dempers I2 and L3 respectively, but vent out exhaust .air when dempers 1:2 and .13,admit make-l1p air:l

As will be described in more detail latenafter @period of time. whichexperence has Vindicated 50 `te be suflcient, V,the air ,flowA indicated' by the narrows et Fia 2 will be reversed with the result wardly through the grille I-fi interthe .fanchamles ber I4. Treated air will be forced through the grille I8 vertically upwardly along the opposite side of the stacked lumber from that which it formerly entered and the treated air will pass horizontally through the channels I0 in a direction opposite to that indicated by the arrows of Figs. 2 and 3, and will pass downwardly through the grille I5 into the suction side of the fans in the fan 4chamber I4, and during this reversal of air movement, the dampersl I 2 and I3 will exhaust air into the duct 9a and out the openings I0a and II. y

Referring to Fig. 3, the mechanism for the treatment and reversal of air ilow will now be described. There are arranged. down the longitudinal center of the fan chamber I4, the plurality of spaced fans 20 which may be mounted on a common shaft 2Ia which is rotated by the motor 22 (Fig. 1). Associated with each fan 20 is the extended surface heating coil 2l and the'humidier. 22. VEach fan 20, coil 2| and humidifier 22 are mounted as a unit within the enclosure formed by the longitudinal walls 23 and by the crosswise wall 24, in which an opening is provided, to form the suction inlet of the Asfindicated by thev arrows of Fig'. 3, the air movement with the danpers 25 and baffles 25a in the'position shown by Fi'g43 is towards the upper vertical side 2'l;ofV the kiln, the air being deflected by the vertical side 21 upwardly through the grilleVV I5 andr then through the horizontal channels between the successive layersof lumber as shown by the arrows in Fig'. 2. The recirculated and outside make-up air enters the fan chamber through thegrille I8.

`The dampers 25 are adapted to be simultan'eously reversed Yas shownby Figs. 3 and 4 by movement of the actuating lever 28, the dampers all-being interconnected bythe lever. When the ,leverV 28 is Vaoljustedto place the dampers 25 in the reverse position to that-shown by Fig. 3, the

. dampers are moved to their other extreme posithe kiln.

rv70 y Y I Y "IZ, I3, I6 and =I`I may be adjusted fromthe apparatus room to control the amount of fresh make- ,upa'ir admitted and exhaust air vented.

dinal side 29 of the compartment I4, in a direc- -tion opposite to that indicated by the arrows of Fig. 3, tobe deflected bythe vertical wall 29, to pass upwardly through the grille I 8, into the dry- :ingchamber 5, and downwardly through the lgrill-I5, and into the suction side ofthe fans, in

aY direction `oppositetothat shown bythe arrows of`Figs. 2 and 3. e e e Q The adjustable baies, 25a are 'rotatablyv attached'at one end to enable the balles to be ad- 'ju'.st'ed t0 guide the air into and outI of the fan vunits so as 'to' provide diagonal air flow towards one end ofthe Fkiln orfcurrents 'of air crosswise The positions 4of thecounterweigntei dampers "I'lie'damper's 25 are pivoted asfshown by Fig. 4 to'rotatev around the ball bearings 30, one of Ysame time, and the entire which is supported in the casing 3I mounted in the roof of the chamber I4, and the other of which is supported in the casing 32, which is mounted in the floor of the fan chamber. The lever 28 which is shown by Fig. 3 is rotatably attached to the damper at the point 33. When the lever 23 is moved from one extreme position to the other, the dampers are caused to take the position shown by the full lines or the position shown by the dotted lines on the left half, facing the drawings, of Fig. 3.

j vIn operation, the apparatus may be rst ad- .shown by the arrows on Figs. 2 and 3 of the drawings.V Referring to Fig. 3 it is seen that the air enters the right hand side (facing the drawings) of the lumber and passes through the channels IG, the air being exhausted at the left hand side of thelumber. Due to the air contacting first with the portion of the lumber adjacent the right hand side ofthe kiln, its effect on the lumber adjacent the left hand side of the kiln is lessened with the result that if the air moves continuously, as shown by the arrows of Figs. 2 and 3, the lumber adjacent the right hand side of the kiln will be driedmore quickly than that adjacent the left hand side of the kiln.

To avoid this, after a period of time, which experience has shown to be sufficient, the dampers 25 are reversed, causing the drying air, as has previously been explained in detail, to enter the lumber at the left hand side of the kiln and to leave the lumber at the right side of the kiln, with the 'result that those portions of lumber which were least dried out when the air flow was in the other direction, are now dried out most, and those portions of lumber which were V'dried out the most when the air flow was in the other direction,'are now dried out'the least, so

, that by reversing the dampers 25 from time to time, the result is that all portions of the lumber become completely dried at substantially the stack may be simultaneous'ly removed.

The baiiles 25al may be adjusted to ensure that the air movement into and out of each fan unit is uniformly distributed. In operation, observation may show that insuicient drying air is passing over one or more portions of the lumber asv compared to other portions and the bailles may be adjusted to direct more or less air; as required, towards such portions Vas are insumciently served.

Whereas, one embodiment of the invention has been described for the purpose of illustration, it should be understood that the invention should not be limited to the exact arrangement described, since many departures rnay be made by those skilled in the art, after having had access torthis disclosure, without departing from the spirit of the invention.

What is claimed is:

ljA dry kiln comprising a pair of fan units arranged in'spaced relationship down along the Vlongitudinal center of said kiln, andV common means comprising a reversible pivoted damper for directing diagonally the air into one of said units and for simultaneously directing diagonally the air from 'the other of said units.

2'. A dry kiln comprising a pair of fan units arranged in spacedrelationship down along the longitudinal center of said kiln, and reversible means independent of the means for rotating the' fans in said units and arranged at the output side of each of said fan units for directing the air into said units from one longitudinal side of said kiln and for directing the air discharged from said units towards the opposite longitudinal side of said kiln, said reversible means comprising a pivoted damper.

3. A dry kiln comprising a drying chamber, a

fan chamber under said drying chamber, a fan unit in said fan chamber faced to blow air longitudinally thereof, and a reversible damper pivoted about a substantially Vertical axis extending through a line extending substantially through the center of said unit and extending substantially parallel to a longitudinal side of said fan chamber, at the output side of said unit for deflecting the air discharged by `said unit towards one or the other longitudinal side o1' said fan chamber.

4. A dry kiln comprising a drying chamber, a fan chamber under said drying chamber, a fan unit in said fan chamber faced to blow air longitudinally thereof, and a reversible damper pivoted about a substantially vertical axis extending through a line extending substantially through the center of said unit and extending substantially parallel to a longitudinal side of said fan chamber, at the input side of said unit for directing the air drawn in by said unit from one or the other longitudinal side of said fan chamber.

5. A dry kiln comprising a -drying chamber, a fan chamber under said drying chamber, a fan unit in said fan chamber faced to blow air longitudinally thereof, a reversible damper pivoted about a substantially Vertical axis extending through a line extending substantially through the center of said unit and extending substantially parallel to a longitudinal side of sai-d chamber, at the output side of said unit for deecting the air discharged by said unit towards one or the other longitudinal side of said fan chamber, and a reversible damper pivoted about a substantially vertical axis extending through a line extending substantially through the center of said unit and extending substantially parallel to a longitudinal side of said fan chamber, at the input side of said unit for directing the air drawn in by said unit from one or the other longitudinal side of said fan chamber.

6. A dry kiln comprising a fan chamber, a. pair of fan units in said chamber arranged in spaced relationship longitudinally thereof and faced to discharge air longitudinally thereof, and a reversible damper pivoted about a substantially vertical axis extending through a line extending substantially through the centers of said units and extending substantially parallel to a longitudinal side of said chamber at the input side of one of said units and at the output side of the other of said units for directing the air drawn in by one of said units from one of the longitudinal sides of said chamber and for directing the air discharged by the other of said units towards the opposite longitudinal side of said chamber.

'7. A dry kiln comprising a fan chamber having a roof and a floor, a plurality of fan units in said chamber spaced along a line extending` 

